9. the man is my father. he is sitting beside my mother. (combine the sentences, using a suitable relative pronoun)
=> the man who sitting beside my mother is my father
10. he has done all the exercises in that book. (change the sentence into the passive voice)
=> all the exercises have been done in that book
11. they had reviewed the lessons carefully, so they did the test very well. (rewrite sentence using because)
=> because they had reviewed the lessons carefully, they did the test very well. 
12. he asked me: “do you want me to go with you?” (change the sentence into reported speech)
=> he asked me if i wanted him to go with me